In the large scale production of wrapped or unwrapped products, such as food items, tiles, compact disks (CDS) or other relatively flat products or packages it is often desirable to arrange groups of individual items into vertical stacks for further wrapping or packaging the vertical stacks of the items into larger trays or containers.
Vertical stacks comprising loose individual items such as crackers, cookies, tiles or small packages or bags stacked upon each other can be produced manually or by using various stacking methods and apparatus. Sometimes, it is advantageous to arrange individual items in a shingled manner prior to stacking of individual items into vertical stacks for easier formation of vertical stacks, or for other considerations in their manufacture. Shingled items are usually delivered to a stacking apparatus in groups or in a continuous stream on a conveyor. Shingling of loose items may be achieved by using several conveyors arranged in series and moving at various speeds which are continuously fed with a stream of loose items. The loose items are delivered to the series of conveyors which place the items in a shingled arrangement from another location. The items are usually delivered to the first conveyor in the series of shingling conveyors by another conveyor moving in the same direction or transverse direction to the flow of the series of shingling conveyors.
Apparatus for stacking shingled items is disclosed, for example, in U.S. Pat. No. 2,708,863 to Payne. Shingled items are delivered via a conveyor into a vertical stack with the aid of movable stop fingers that rise up to prevent forward movement of items, thus causing shingled items to pile on top of each other forming a vertical stack. After a vertical pile is formed, the fingers lower to allow continuous forward movement of the vertical stack.
U.S. Pat. No. 3,088,604 to Nilsson discloses stacking shingled items (newspapers) into vertical stacks on a support platform and transporting the stacks on the support platform to another conveyor.
U.S. Pat. No. 3,124,059 to Labombarde discloses stacking of shingled items into vertical stacks. Shingled items delivered by a conveyor fall down a chute. The items are guided by rollers to fall flat without tilting.
U.S. Pat. No. 3,195,739 to Hein et al., discloses a piling device that moves and stacks items from an upper platform to a lower table by using swinging arms that pick up the items at the end of an upper platform and slide them to a lower level.
U.S. Pat. No. 3,331,516 to Gubeli discloses a method and apparatus for stacking of shingled items delivered by a conveyor, into vertical piles (stacks) wherein shingled items fall down the chute at the end of the conveyor. Their movement is guided by a pressure rail at the end of the conveyor.
U.S. Pat. No. 3,403,033 to Griner discloses shingling of flat biscuits wherein pieces arrive in a flat position and are separated from each other, stacked in tilted overlapping position and then in non-overlapping completely vertical edge position for packing.
U.S. Pat. No. 3,429,416 to Provost et al, discloses a transfer conveyor apparatus for delivering rows of articles to several infeed conveyors moving at a right angle to the transfer conveyor.
U.S. Pat. No. 3,488,917 to Oswald et al. discloses transportation and packing of shingled book matches. A wiper blade prevents shingled products from falling down when a carriage intermittently moves backwards.
U.S. Pat. No. 3,638,538 to Sullivan discloses stacking of shingled items into vertical piles. After a predetermined number of items has been counted, a vertical stopper arm is moved upward and forward to move the items toward the closed door stacking them into a vertical position. The arms drop down sharply when they reach the end point and the items are in a complete vertically stacked position. The door is then open to allow the stacked items to be moved to another transporter. The arms move shingled items to a stopper door, densifying the stack along the way and eventually stacking items in completely vertical stacks.
U.S. Pat. No. 3,874,522 to Rana discloses converting of a loose shingle stack of signatures (any flat products) into a dense stack of shingled signatures.
U.S. Pat. No. 4,282,964 to Hogenkamp et al, discloses a device for transferring articles arriving in transverse rows on an upper conveyor to a lower removal belt. The device comprises a transfer belt pivotally mounted for alignment with the plane of the delivery belt and the plane of the removal belt.
U.S. Pat. No. 4,432,685 to Stauber discloses an overhead stop plate. In a prestacker that stacks products arriving as shingled piles via conveyor to the prestacker, the product falls down a chute forming vertical stacks. However, before falling, each single piece of product hits a stop plate that stops the piece from moving forward and guides it to fall down the chute.
U.S. Pat. No. 5,095,684 to Walker et al. discloses an apparatus for conveying individual, flat laying products (such as cookies) from a horizontal position to shingled overlapping stacks and to a completely vertical edge position using several conveyors moving at different speeds. The speed is varied depending on the heights of the cookies. The cookies are counted, and a predetermined number of cookies, in completely vertical position are then packaged in cookie trays. Stacking shingled products in a horizontal position in vertical stacks (on top of each other) is not disclosed.
U.S. Pat. No. 5,287,952 to Radaelli discloses a device for transferring of rows of items from an upper conveyor belt to a lower conveyor belt arranged at a right angle. The device comprises two intermediate shelves. The first shelf is pivotally mounted to align with the end of the downward inclined upper conveyor to receive rows of items by inclining upwards. Then, it is aligned in a horizontal position with the second shelf to transfer the rows of items to the horizontal second shelf. The second shelf then moves downward for alignment with the edge of the lower conveyor and to transfer rows of items to the lower conveyor.
U.S. Pat. No. 5,460,843 to Greene discloses a device for packaging cookies. Prior to packaging, the cookies are dropped to a lower level conveyor with the help of an overhead belt system that orients cookies into a vertical position. The last cookie of each stack with a predetermined number of cookies is inverted. The cookies are then stacked in vertical position in stacks and packaged with the last cookie being inverted and facing an opposite direction compared to the rest of the stack.
U.S. Pat. No. 5,640,833 to Gerber discloses a device for transferring items from a supply belt on a transverse belt. The device comprises an intermediate supply conveyor belt with a tilting end for alignment with the surface of the transverse belt for gentle discharging items onto the transverse belt.
None of the stacking apparatus for forming vertical stacks from groups of shingled individual items disclosed in the cited references teach or suggest apparatus comprising lowering arms, or beams, that gently transport items to be stacked to a lower stacking level, wherein the items remain in a substantially horizontal position while being lowered by the lowering arms, and the bottom item of the forming stack remains on the lowering arms in substantially horizontal position during the entire time it remains in contact with the lowering arms. Also the references do not disclose an infeed system comprising a series of conveyors for shingling and separating a stream of items into groups of predetermined number which employs a tilting conveyor for gentle receiving of groups of items.
The present invention provides a method for producing vertical stacks and a stacking apparatus comprising at least one set of lowering arms or beams that lower items continuously delivered by an infeed conveyor system in shingled groups, to a lower stacking level, while forming vertical stacks. The items remain in an at least substantially horizontal position all or substantially all the time during the stacking cycle. The infeed system, comprising a series of conveyors moving at various speeds, is capable of gently: a) receiving items delivered to the infeed system in the same direction, or at a right angle to the direction of the flow of the infeed system, b) breaking the stream of items into groups of predetermined number, c) shingling the items in the groups, and d) delivering groups of shingled items to the stacking apparatus at regular intervals synchronized with the stacking cycle of the lowering arms. The apparatus allows for efficient and easy handling of large numbers of items per minute. It can be used with little or no adjustment to handle items of different shape, can be easily adjusted to handle groups of items containing different numbers of items per group, and is virtually jam-free. It is also very gentle on the items being stacked. The apparatus is highly tolerant to misoriented or irregularly placed items, irregularly shaped or broken items, and is capable of curing most of the misorientations and other irregularities during the stacking process to form regularly shaped stacks.